Method of treating tubular goods while simultaneously testing the interior thereof

ABSTRACT

A method of treating tubular goods with an inhibitor which comprises forcing the inhibitor into intimate contact with the surface area of the metal goods to be treated by utilizing high pressure techniques. The inhibitor is forced into the multitude of cracks and minute voids located in the irregular surface of the metal, so that after the pressure is removed and the inhibitor drained from the surface, a coating of the inhibitor is left within the outer boundary of the metallic surface, thereby forming a protective film on the surface of the metal. Advantage is taken of this expedient to provide a method of simultaneously treating pipe surfaces with an inhibiting agent, while at the same time the pipe joints are hydrostatically tested.

ite ttes lglehart et a1. I

[ METHOD OF TREATING TUBULAR GOODS WHILE SIMULTANEOUSLY TESTING THEINTERIOR THEREOF [75] Inventors: Jesse ll. lglehart; Hilary H. Iglehart,

both of Odessa, Tex.

[73] Assignee: Spinning Pipe Service, Inc., Odessa,

Tex.

[22] Filed:- Nov. 23, 1971 [21] Appl. No.: 201,448

[ Jan. 22, 1974 10/1969 Ginsburgh et al. 138/97 10/1918 Stern 138/97 XPrimary ExaminerEdward G. Whitby Attorney, Agent, or Firm-Marcus L.Bates [5 7] ABSTRACT A method of treating tubular goods with aninhibitor which comprises forcing the inhibitor into intimate contactwith the surface area of the metal goods to be treated by utilizing highpressure techniques. The inhibitor is forced into the multitude ofcracks and minute voids located in the irregular surface of the metal,so that after the pressure is removed and the inhibitor drained from thesurface, a coating of the inhibitor is left within the outer boundary ofthe metallic surface, thereby forming a protective film on the surfaceof the metal.

Advantage is taken of this expedient to provide a method ofsimultaneously treating pipe surfaces with an inhibiting agent, while atthe same time the pipe joints are hydrostatically tested.

7 Claims, 5 Drawing Figures PMETH] JAN22 I974 FIG.

BACKGROUND OF THE INVENTION Metallic goods used in conjunction with oilfield exploration and production are subjected to the deleteriouseffects of corrosion, which includes all sorts of known detrimentalactions which occurs to metal when it is placed in such an environment.The corrosion engineer, when faced with a specific type of corrosionproblem, can usually select an inhibiting agent which will at leastmitigate the corrosive attack upon the metallic goods. However,corrosion problems in the oil field is usually restricted to problemsassociated with production; specifically, sweet, sour, and condensatecorrosion problems.

The problem of corrosion commences when tubular goods are stacked in ayard, and rapidly accelerates when the goods are placed in use, as forexample, during the drilling process, the. use of corrosive muds contactthe drill pipe during earth boring processes. After the well iscompleted and production tubing installed, the problem of corrosionbecomes more pronounced.

In the oil production and drilling art, it is desirable to test jointsof pipe whenever possible in order to detect the presence of flawstherein. It is especially desirable to test threaded connectionswhere'one joint of pipe is threadedly secured to another joint to form astring of pipe, which is disposed within a bore hole.

The term corrosion is intended to mean any type attack upon the surfaceof the metal which reduces its structural integrity and includesoxidation, electrolitic, acid, and hydrogen sulfide corrosion. There area number of chemicals available to industry which are suitable for useas an inhibiting agent. The term inhibitor or inhibitor agent includesany chemical additive which reduces the corrosion of the metallic goods,and

specifically the organic inhibitors such as hexametaphosphate and otherpolyphosphates of soda, for example. The protective deposits from two ormore different inhibitors used together often is more effective thaneither one by itself, and it is this type inhibitor which is marketed byoil well service companies.

The preferred inhibitors used herein are identified as follows: KP9,K147, and KPlO, all trade names, and marketed by Treat-O-Lite company ofMidland, Tex.

Reference is also made to my co-pending Pat. application Ser. No.195,658 filed Nov. 4, 1971, for a more comprehensive understanding ofthe action of a film of corrosion inhibitor upon the mechanical goods.

Pipe testing is sometime conducted with the pipe being verticallydisposed within a borehole by the use of various prior art apparatus ortools made specifically for this purpose, as exemplified by the patentto Dumond Pat. No. 3,503,249 (and the art cited therein) to whichreference is made for further background of this invention.

It would be advantageous to be able to treat metallic goods with acorrosion inhibitor so that the metallic goods are protected from thedeleterious effects of corrosion from the time that the goods are placedin storage and continuing for a long time after the goods are placed inuse. Furthermore, it would be desirable to inhibit the goods'againstcorrosion after they are placed into production by an improved methodwhich would preclude occurrence of corrosion until a proper corrosionprogram has been undertaken in the field. Moreover, it would beadvantageous to be able to treat the goods in conjunction with someprocess to which the goods already are subjected.

SUMMARY OF THE INVENTION The present invention comprehends the treatmentof tubular goods with an inhibitor wherein the inhibiting agent isforced into intimate contact with the entire exposed surface area of themetallic goods which is to be subjected to corrosion attacks, so as toform a surface film which precludes or reduces corrosion attacks. Theinvention is carried out by isolating the surface-of the goods to betreated and flow connecting the inhibiting agent to the isolated area,whereupon the pressure of the inhibiting agent is increased to a valuewhich forces the agent to be dispersed'into the natural cavities andcrevasses present in the surface of the goods. Several differentembodiments of the invention teach the application of pressure to theagent. One form of the invention includes the treatment of the metalgoods in conjunction with internal testing of drill pipe and productiontubing.

A primary object of this invention is to treat the exposed surface areaof the goods so as to mitigate the effects of corrosion.

Another object of the invention is to expose the external or internalsurface area of metallic goods to an inhibiting agent under a tremendouspressure so as to force the agent into intimate contact with the surfaceto be treated.

A further object of this invention is to simultaneously test and treatmetallic goods in a new and unobvious manner.

A still further object of this invention is to hydrostatically test thestructural integrity of tubular goods while simultaneously treating aperipheral surface thereof with a corrosion inhibitor.

Another and still further object is to utilize commercially availablecorrosion inhibitors in an improved manner.

An additional object of this invention is to mitigate the deleteriouseffects of corrosion by subjecting the metallic goods to a corrosioninhibiting agent with the inhibitor being forced into the metal byutilizing tremendous pressure differentials.

These and various other objects and advantages of the invention willbecome readily apparent to those skilled in the art upon reading thefollowing detailed description and claims and by referring to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a broken view ofadiagrammatical representation of a borehole which sets forth one formof the FIG. 5 is a schematical representation which diagrammaticallysets forth an important teaching of the present invention.

DETAILED DESCRIPTION OF THE VARIOUS EMBODIMENTS Throughout the variousfigures of the drawings, like or similar numerals, wherever possible,refer to like or similar elements.

As seen illustrated in FIG. 1, a tubing string is made up of individualjoints of tubing 11, 11' joined together by a coupling member 12, andincludes the usual peripheral wall surface 13. A testing tool 14, thedetails of which are known to those skilled in the art, has an outerperpheral wall surface 14; and, between the tubing and the mandrel 15there is formed an annular area 16. Fluid conduit 17 is flow connectedto and supports the mandrel, with the mandrel having spaced apartpacking elements 18 and 19 disposed thereon. The distance between thespaced apart packers defines the length of the annulus.

Removable fluid conduit 20 is connected to a source of a liquid chemicalinhibiting agent by means of a high pressure pump 21. Valve 22 controlsthe flow of fluid from the pump into the mandrel while valve 23 releivesthe pressure within the mandrel. Those skilled in the art willunderstand that packers l8 and 19 are set when pressure is applied at17, with the pressure output of pump 21 also being effected upon annulararea 16. Hence the surface 13 of the tubing is isolated from theremainder of the tubing by the packers.

In FIG. 2 the elongated tubular member 11, which can be productiontubing, drill pipe, or any other tubular goods, is provided withremovable closure members 25 and 26, with flow conduit 27 beingconnected thereto so as to fill the interior 13 of the pipe with aliquid chemical inhibiting agent. Conduit 27 can be connected to conduit20 of FIG. 1 if desired.

Looking now to the details of FIGS. 3-5, there is seen apparatus 28which includes a vertically upstanding high pressure chamber 29 which isbottom supported by structure 30. An upwardly opening flange 31 isdisposed at the upper extremity of the chamber. Cantilever arm 32 isattached to and extends above the opening, and is reinforced by web 33which also aids in supporting the illustrated platform.

Hydraulically actuated cylinder 34 has the usual flow conduits 35attached thereto, with the cylinder including a piston having a pistonrod 36 journalled at 37 to a closure member 38. The closure memberpreferably is in the form of a round door which is journaled to theflange and arm at 39, and can be moved from the opened into the closedposition, and vise versa.

Web 40 supports a latch member 41 in journaled relationship therewith,with the latch member being adapted to engage the closure member so asto securely and sealingly hold it locked into the closed position.

4 The interior 42 of the chamber contains a plurality of tubular goods11 which may be inserted and removed therefrom through the openingformed by the flange. A ladder 43 leads to the working platform, withbanister 44 being optionally provided for safety.

In FIG. 5, the supply of liquid inhibitor has an outflow connection 27connected to a high pressure pump 21 which in turn is flow connected toconduit 45. Conduit 45 leads to heat exchanger element 46 located withinheater 47, with the outlet of the heating element being connected toconduit 48 which leads to chamber 49. The chamber 49 can be anytreatment chamber such as exemplified by tubular members 11 of FIG. 1,

5 11 of FIG. 2, or 29 of FIG. 3. Stack 50 emits flue gases to theatmosphere while a fuel burner is connected to a suitable source of airand fuel by means of conduit 51.

In the operation of the first embodiment as illustrated in FIG. 1, thetool testing apparatus 10 is generally dis- 10 posed within a tubingstring 11 so as to hydrostatically test the threaded connections betweeneach joint as well as to subject the entire inside pipe surface to ahigh pressure in order to practice the present invention. Pump 21 isconnected to an inhibiting agent which can 15 be a water dispursed or anoil soluble chemical addi- 20 20, through conduit 17, and into theannular area 16.

Prior to the chemical flowing into the annulus, packers 18 and 19 areset," thereby isolating the surface of the goods to be treated. As thepressure of the inhibiting agent increases it completely fills theannulus, thereby 25 increasing the presure of the inhibiting agent uponthe isolated surface to a value below the bursting strength of the pipeso as to cause the agent to displace any remaining compressible fluidfrom the isolated surface.

The pits, crevasses, and minute cracks normally found 30 in theirregular surface of any tubular goods will be contacted by the chemicalas the pressure increases. The increase in pressure precludes capillaryaction causing adherence of minute air pockets to the surface of themetal. When the pressure reaches several thousand psi it is believedthat the gases adjacent to and included within the surface of the metalis driven into solution with the agent, or, on the other hand, the gaseswill be compressed to an infinitesimally small volume. As the pressurecontinues to rise within the annulus,

40 the inhibiting agent is forced into intimate contact with 45 gauge,and held for a predetermined length of time in order to determinepossible leakage of threaded fastener l2, whereupon the pressure isreleased by using the valve 23, with excess inhibitor agent preferablyreturning to the source. With close fitting packers, it is possible toleave the annulus filled with the inhibitor while the tool is moved tothe next joint to be tested.

In the embodiment of FIG. 2, tubular member 13 is to be treated with aninhibitor agent, and therefore the interior surface of the goods isisolated by means of closure members 25 and 26. Conduit 27 is connectedto pump 21, for example, which in turn is connected to a suitable sourceof treatment fluid. The pressure exerted on the interior surface 13 tobe treated is increased to a value slightly below the designed breakingstrength strength of the pipe. After completion of the treatment, theend caps 25, 26 are removed, with the excess fluid contained therewithinfirst being retrieved by means of flow conduit 27.

In FIGS. 3 and 4, a workman ascends ladder 43 onto the platform so as tosupervise the joints of pipe as they are each placed within chamber 29.After the chamber is filled to capacity with pipe, hydraulic cylinder34, which is flow connected at 35 to a source of fluid pressure, isactuated thereby causing piston rod 36 to move the closure member 38into sealing engagement with the flange. Latch 41 retains the closuremember sealingly engaged with the flange 31 so as to isolate the surfaceof the goods to be treated. Conduit 27 enables an inhibiting agent toflow to and from a source into contact with the isolated pipe to betreated. As the liquid flows into the interiorof the chamber, it issubjected to an increasing pressure which is maintained below thebreaking strength of the chamber for several minutes in duration so asto enable any compressible gases which were inadvertently or necessarilyleft on the surface of the metal to enter into solution. After treatmentof the tubular goods, the pressure is released at 27, closure member 38is moved to the open position, and the tubular goods removedfrom thetreatment chamber. 7

In FIG. 5, if desired, the source of chemical 29 can be heated byelement 46 prior to being introduced into the treatment chamber 49 tothereby accelerate the treatment process. This expedient can be used incarrying out any one of the above described treatment operations.

Accordingly, in each of the above procedures, it will be noted that thesurface of the goods to be treated has first been isolated, whereupon aninhibiting agent is then flow connected from a source to the isolatedarea. Thereafter, the pressure of the inhibiting agent upon the isolatedsurface of the goods is increased to thereby cause the agent to displacecompressible fluid from the isolated surface by either compressing thefluid so as to reduce it in volume'or to cause the fluid to enter intosolution. The increased pressure causes the inhibiting agent to beforced into the metal exposed to the agent, so that the outer boundaryof the metal is coated with the inhibitor. The residual inhibitor, thatis, the inhibitor which is not required to coat the surface of the pipeor the inhibitor which is not required for carrying out the next batchoperation is returned to the source.

I claim:

1. Method of treating tubular goods with an inhibitor comprising:

1. isolating the interior surface of the goods to be treated by placinga plurality of pipe joints into an enclosure means;

2. flow connecting an inhibiting agent from a source upon the interiorof said enclosure means so as to cause the agent to coat the interiorsurface of the 5 goods and to displace any compressible fluid which maybe present on the isolated surface thereof; 4. and, removing theresidual inhibitor from the isolated surface after carrying out step(3). I 2. The method of claim 1, and further including the followingsteps:

7. movably affixing a closure means to the enclosure means; and

8. actuating the closure means by hydraulic ram.

3. The method of claim 1, wherein:

the enclosure means is an upright vessel having a closure means at theupper extremity thereof through which the tubular goods may betransported.

4. Method of testing coupling members of a series connected string ofpipe joints while simultaneously treating the interior surface thereofwith an inhibitor comprising the steps of:

l. placing spaced packer elements within the pipe string with thecoupling members being disposed therebetween so as to isolate at leastone half of a marginal interior longitudinally extending length ofadjacent joints of pipe from the ambient;

2. flow connecting an inhibiting agent from a source to the isolatedarea located between the packers;

3. increasing the pressure of the inhibiting agent to coat the isolatedsurface and to displace any compressible fluid which may be present onthe isolated surface;

4. carrying out step (3) while at the same time hydrostatically testingthe structural integrity of the coupling member of the pipe string byadjusting the pressure to a value which is representative of the workingpressure of the pipe joint;

5. removing the residual inhibitor from the isolated surface aftercarrying out step (3).

5. The method of claim 4 wherein said inhibiting agent includes an oilsoluble organic liquid inhibitor.

6. The method of claim 4 wherein said inhibiting agent includes a waterdispersed inhibitor.

7. The method of claim 4 wherein the inhibiting agent of step (2)includes a liquid which wets the entire surface undergoing treatment.

upon the isolated surface so as to cause the agent i

2. flow connecting an inhibiting agent from a source to the isolatedarea located between the packers;
 2. The method of claim 1, and furtherincluding the following steps:
 2. flow connecting an inhibiting agentfrom a source of supply to the interior of said enclosure means; 3.increasing the pressure of the inhibiting agent upon the interior ofsaid enclosure means so as to cause the agent to coat the interiorsurface of the goods and to displace any compressible fluid which may bepresent on the isolated surface thereof;
 3. The method of claim 1,wherein: the enclosure means is an upright vessel having a closure meansat the upper extremity thereof through which the tubular goods may betransported.
 3. increasing the pressure of the inhibiting agent upon theisolated surface so as to cause the agent to coat the isolated surfaceand to displace any compressible fluid which may be present on theisolated surface;
 4. carrying out step (3) while at the same timehydrostatically testing the structural integrity of the coupling memberof the pipe string by adjusting the pressure to a value which isrepresentative of the working pressure of the pipe joint;
 4. Method oftesting coupling members of a series connected string of pipe jointswhile simultaneously treating the interior surface thereof with aninhibitor comprising the steps of:
 4. and, removing the residualinhibitor from the isolated surface after carrying out step (3).
 5. Themethod of claim 4 wherein said inhibiting agent includes an oil solubleorganic liquid inhibitor.
 5. removing the residual inhibitor from theisolated surface after carrying out step (3).
 6. The method of claim 4wherein said inhibiting agent includes a water dispersed inhibitor. 7.The method of claim 4 wherein the inhibiting agent of step (2) includesa liquid which wets the entire surface undergoing treatment.
 7. movablyaffixing a closure means to the enclosure means; and
 8. actuating theclosure means by hydraulic ram.